JP7074144B2 - Rotating electric machine control device - Google Patents

Description

The present invention relates to a rotary electric machine control device that drives and controls a rotary electric machine having an open winding via two inverters.

In the 2007 IEEE paper "Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM" by V. Oleschuk et al. A control device for driving and controlling a rotary electric machine by switching and controlling inverters provided one by one is disclosed. On the other hand, as a well-known form, for example, there is a method in which one inverter is switched and controlled on the other end side of a Y-shaped winding to which one end side of each of the three-phase windings is connected to drive and control a rotary electric machine. In a system using an open winding and two inverters, if the DC voltage is the same, the line voltage of the AC voltage of the winding is higher than in a system using a Y-shaped winding and one inverter. It is possible to operate the rotary electric machine with a higher output.

In the introduction of the paper by V. Oleschuk et al., The magnitude of the ripple of the current flowing through the winding is reduced by making the phase of the carrier signal that generates the pulse for switching control of the two inverters different from each other. It is stated that it can be done. V. Oleschuk et al. Further note that generating pulses synchronously rather than asynchronously with carrier signals allows better control for medium / high power applications. There is. However, in both the asynchronous method and the synchronous method, the two inverters are switched and controlled by the same control method, for example, as shown in Table 1 below.

In Table 1, "CPWM" is continuous pulse width modulation, "DPWM" is discontinuous PWM, and "1-Pulse" is rectangular wave modulation (1-Pulse Modulation). , "Asynchronous" indicates asynchronous modulation that is asynchronous to the rotation of the rotary electric machine, and "synchronous" indicates synchronous modulation that is synchronized with the rotation of the rotary electric machine. For example, in continuous pulse width modulation, a pulse is generated based on the magnitude relationship between the amplitude of an AC waveform (for example, an AC voltage waveform) as an output command and the amplitude of the waveform of a triangular carrier (including a saw wave). Including the case where the PWM waveform is directly generated by digital calculation without comparison with the carrier). The carrier is determined according to a control cycle such as a calculation cycle of a microcomputer or an operation cycle of an electronic circuit, and is not constrained (not synchronized) with the rotation speed or rotation angle (electric angle) of a rotating electric machine.
Such a modulation method is called asynchronous modulation. On the other hand, in the square wave modulation, one pulse is output for each cycle of the electric angle of the rotary electric machine, and the pulse is synchronized with the rotation speed and the rotation angle (electric angle) of the rotary electric machine. Therefore, the square wave modulation is a synchronous modulation method. Discontinuous pulse width modulation can be realized by either an asynchronous method or a synchronous method.

However, the inverter switching control method is not limited to these modulation methods. The switching control method is preferably determined by various factors such as the torque required for the rotary electric machine, the rotation speed, and the voltage on the DC side so as to enable operation with higher system efficiency. Therefore, there is still room for improvement in properly controlling the two inverters provided at both ends of the open winding with higher system efficiency.

V. Oleschuk, R. Bojoi, G. Griva, F. Profumo, “Dual Inverter-Fed Traction Drive with DC Sources Power Balancing Based on Synchronized PWM”, Conference Paper / June 2007, 1-4244-0743-5 / 07, IEEE, p.260-265

In view of the above background, it is desired to provide a technique for appropriately controlling two inverters provided at both ends of the open winding.

In view of the above, the rotary electric machine control device for driving and controlling a rotary electric machine having a plurality of phases of open windings independent of each other via a first inverter and a second inverter is available.
The first inverter is connected to one end side of the multi-phase open winding to convert power between direct current and multi-phase alternating current.
The second inverter is connected to the other end of the multi-phase open winding to convert power between direct current and multi-phase alternating current.
In the first inverter and the second inverter, the arm for one AC phase is composed of a series circuit of an upper switching element and a lower switching element, respectively.
As the control method of the first inverter and the second inverter, pulse width modulation control in which a plurality of pulses having different patterns are output in one cycle of the electric angle and the upper switching element of the arm of all the plurality of phases are turned on. At least two of the active short circuit control in which the lower switching element of the arm in the state or the multiple phases is turned on and the square wave control in which one pulse is output in one cycle of the electric angle. With a control method
The first inverter and the second inverter can be controlled by the independent control methods.
One of the plurality of control methods is defined as the first control method, and one control method different from the first control method is used as the second control method.
A rotary electric machine control device having a control mode in which the first inverter is controlled by the first control method and the second inverter is controlled by the second control method.

As a control method for controlling the inverter, various methods according to operating conditions such as the rotation speed and torque of the rotary electric machine are known. When two inverters are provided as in this configuration, it is possible to generate an AC voltage having an amplitude larger than the voltage on the DC side. However, the rotary electric machine control device does not always need to control the two inverters so that the amplitude of the alternating current becomes the largest, but may control the two inverters so that the required amplitude can be obtained. By controlling the first inverter and the second inverter by independent control methods, it is possible to flexibly control the two inverters according to the operating conditions of the rotary electric machine. Furthermore, by having a control mode in which the first inverter and the second inverter are controlled by different control methods, it is possible to increase the flexibility of control and drive and control the rotary electric machine with high efficiency according to the operating conditions of the rotary electric machine. can. That is, according to this configuration, it is possible to appropriately control the two inverters provided at both ends of the open winding.

Further features and advantages of the rotary electric machine control device will be clarified from the following description of the embodiments described with reference to the drawings.

Schematic block diagram of rotary electric drive system Vector diagram of rotary electric drive system using two inverters The figure which shows the control area of a rotary electric machine by the relationship between a rotation speed and a torque. Vector diagram of first control mode Vector diagram of second control mode Vector diagram of the third control mode Vector diagram of 4th control mode Waveform diagram showing an example of U-phase voltage command in the first control mode Waveform diagram showing an example of U-phase voltage command in the second control mode Waveform diagram showing another example of U-phase voltage command in the second control mode Waveform diagram showing an example of U-phase voltage command in the third control mode Waveform diagram showing another example of U-phase voltage command in the third control mode Waveform diagram showing an example of U-phase voltage command in the 4th control mode Waveform diagram showing an example of U-phase voltage in the 4th control mode Waveform diagram showing an example of U-V phase voltage in the 4th control mode

Hereinafter, an embodiment of a rotary electric machine control device for driving and controlling a rotary electric machine having a plurality of phases of open windings independent of each other via two inverters will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a rotary electric machine drive system including a rotary electric machine control device 1 (MG-CTRL). The rotary electric machine 80 is a driving force source for wheels in a vehicle such as an electric vehicle or a hybrid vehicle. The rotary electric machine 80 is an open winding type rotary electric machine having a plurality of phases (three phases in this embodiment) of stator coils 8 (open windings) that are independent of each other. One inverter 10 is connected to both ends of the stator coil 8 to convert electric power between direct current and alternating current having a plurality of phases (here, three phases), which are independently controlled. That is, the first inverter 11 (INV1) is connected to one end side of the stator coil 8, and the second inverter 12 (INV2) is connected to the other end side of the stator coil 8. Hereinafter, when it is not necessary to distinguish between the first inverter 11 and the second inverter 12, it will be simply referred to as an inverter 10.

The inverter 10 includes a plurality of switching elements 3. An IGBT (Insulated Gate Bipolar Transistor) or a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used for the switching element 3. FIG. 1 illustrates a mode in which an IGBT is used as the switching element 3. The first inverter 11 and the second inverter 12 have the same circuit connection form, but may be configured by using the same type of switching element 3, or may be configured by using different types of switching elements 3. You may be. Details will be described later, but for example, the first switching element 31 constituting the first inverter 11 is a Si-IGBT or Si- MOSFET, and the second switching element 32 constituting the second inverter 12 is a SiC- MOSFET ( Silicon Carbide --Metal Oxide Semiconductor FET), SiC-SIT (SiC --Static Induction Transistor), GaN-PWM (Gallium Nitride - MOSFET), etc. It is preferable that the switching element has a relatively small switching loss at the time of transition.

In each of the two inverters 10, the arm 3A for one AC phase is composed of a series circuit of the upper switching element 3H and the lower switching element 3L. Each switching element 3 is provided with a freewheel diode 35 in parallel with the direction from the negative electrode FG toward the positive electrode P (the direction from the lower side to the upper side) as the forward direction. Further, in the present embodiment, the two inverters 10 are connected to independent DC power supplies 6. That is, the first floating ground FG1 which is the negative electrode FG of the first inverter 11 and the second floating ground FG2 which is the negative electrode FG of the second inverter 12 are independent of each other. Further, a DC link capacitor 4 (smoothing capacitor) for smoothing the DC voltage is provided between the inverter 10 and the DC power supply 6.

Specifically, the first inverter 11 in which the arm 3A for one AC phase is composed of a series circuit of the first upper stage side switching element 31H and the first lower stage side switching element 31L is a first DC link capacitor on the DC side. 41 (first smoothing capacitor) is connected, the DC side is connected to the first DC power supply 61, and the AC side is connected to one end side of the multi-phase stator coil 8 between the DC and the multi-phase AC. Convert power. The second inverter 12 in which the arm 3A for one AC phase is composed of a series circuit of the second upper-stage side switching element 32H and the second lower-stage side switching element 32L has a second DC link capacitor 42 (second smoothing) on the DC side. A capacitor) is connected, the DC side is connected to the second DC power supply 62, and the AC side is connected to the other end side of the multi-phase stator coil 8 to convert power between the DC and the multi-phase AC. ..

In the present embodiment, the first DC power supply 61 and the second DC power supply 62 are DC power supplies having the same rating such as voltage, and the first DC link capacitor 41 and the second DC link capacitor also have the same rating such as capacity. It is a capacitor of. The rated voltage of the DC power supply 6 is about 48 to 400 volts. The DC power supply 6 is composed of, for example, a secondary battery (battery) such as a nickel hydrogen battery or a lithium ion battery, an electric double layer capacitor, or the like. The rotary electric machine 80 can function as both an electric machine and a generator. The rotary electric machine 80 converts the electric power from the DC power source 6 into power via the inverter 10 (power running). Alternatively, the rotary electric machine 80 converts the rotational driving force transmitted from the wheels or the like into electric power, and charges the DC power supply 6 via the inverter 10 (regeneration).

As shown in FIG. 1, the inverter 10 is controlled by the rotary electric machine control device 1. The rotary electric machine control device 1 is constructed with a logic circuit such as a microcomputer as a core member. For example, the rotary electric machine control device 1 performs current feedback control using a vector control method based on a target torque of the rotary electric machine 80 provided from another control device such as a vehicle control device (not shown), and is an inverter. The rotary electric machine 80 is controlled via 10. The control method of the inverter 10 includes a plurality of control methods such as torque control, current control, and voltage control. In the present embodiment, the inverter 10 is controlled by voltage control.

The actual current flowing through the stator coil 8 of each phase of the rotary electric machine 80 is detected by the current sensor 15, and the magnetic pole position of the rotor of the rotary electric machine 80 at each time point is detected by the rotation sensor 13 such as a resolver. The rotary electric machine control device 1 executes current feedback control using the detection results of the current sensor 15 and the rotary sensor 13. The rotary electric machine control device 1 is configured to have various functional parts for current feedback control, and each functional part is realized by the cooperation of hardware such as a microcomputer and software (program). To.

As shown in FIG. 1, the control terminals (gate terminals in the case of IGBTs and FETs) of each switching element 3 constituting the inverter 10 are connected to the rotary electric machine control device 1 via the drive circuit 2 (DRV). , Each is individually switched and controlled. A high-voltage circuit (system connected to the DC power supply 6) for driving the rotary electric machine 80 such as the inverter 10 and a low-voltage circuit (from 3.3 volts) such as the rotary electric machine control device 1 centered on a microcomputer or the like. The operating voltage (power supply voltage of the circuit) is significantly different from the operating voltage system of about 5 volts. The drive circuit 2 relays by increasing the drive capability of the drive signal (switching control signal) for each switching element 3 (the ability to operate a subsequent circuit such as voltage amplitude and output current). The first drive circuit 21 relays the switching control signal to the first inverter 11, and the second drive circuit 22 relays the switching control signal to the second inverter 12.

The rotary electric machine control device 1 has, for example, pulse width modulation (PWM) control and a square wave as the form of the switching pattern (form of voltage waveform control) of the switching element 3 constituting the first inverter 11 and the second inverter 12. It has two control forms, wave control (1 pulse control (1-Pulse)). Further, as a form of field control of the stator, the rotary electric machine control device 1 has a maximum torque control that outputs the maximum torque with respect to the current flowing through the rotary electric machine 80 and a maximum efficiency control for driving the motor with the maximum efficiency with respect to the motor current. It has field adjustment control such as normal field control such as, weak field control that weakens the field magnetic flux by passing a field current (d-axis current Id) that does not contribute to torque, and strong field control that strengthens the field magnetic flux. ing.

Further, the rotary electric machine control device 1 can execute shutdown control or active short circuit control (ASC) as fail-safe control when an abnormality is detected in the inverter 10 or the rotary electric machine 80. The shutdown control is a control in which the switching control signals to all the switching elements 3 constituting the inverter 10 are inactive and the inverter 10 is turned off. Active short circuit control is a control in which either one of the upper switching element 3H of all the arms 3A of multiple phases or the lower switching element 3L of all the arms 3A of multiple phases is turned on and the other side is turned off. be. The case where the upper switching element 3H of all the arms 3A of the plurality of phases is turned on and the lower switching element 3L of all the arms 3A of the plurality of phases is turned off is referred to as an upper active short circuit control. Further, the case where the lower switching element 3L of all the arms 3A of the plurality of phases is turned on and the upper switching element 3H of all the arms 3A of the plurality of phases is turned off is referred to as lower active short circuit control.

By the way, when the inverters 10 are connected to both ends of the stator coil 8 as in the present embodiment, when one of the inverters 10 is short-circuited by active short circuit control, the multi-phase stator coil 8 becomes the one inverter. It is short-circuited at 10. That is, one of the inverters 10 becomes a neutral point, and the stator coil 8 is connected in a Y shape. Depending on the control method, the open winding type rotary electric machine 80 is controlled via two inverters 10, and the Y-type connection is rotated via one inverter 10 (inverter 10 on the side not controlled by the active short circuit). It is possible to realize a form in which the electric machine 80 is controlled. Therefore, in the present embodiment, not only the fail-safe control but also the active short circuit control is included as a control mode that can be selected by the normal control.

That is, as the control method of the first inverter 11 and the second inverter 12, the rotary electric machine control device 1 has pulse width modulation control in which a plurality of pulses having different patterns are output in one cycle of the electric angle, and arms of all the plurality of phases. Active short circuit control that turns on the upper switching element 3H of 3A or turns on the lower switching element 3L of all the arms 3A of multiple phases, and a square that outputs one pulse in one cycle of the electrical angle. Has wave control. Here, one of these plurality of control methods is referred to as a first control method, and one control method different from the first control method is referred to as a second control method. For example, when the first control method is pulse width modulation control, the second control method is active short circuit control or square wave control. The rotary electric machine control device 1 has a control mode in which the first inverter 11 is controlled by the first control method and the second inverter 12 is controlled by the second control method. Of course, the rotary electric machine control device 1 also has a control mode in which the first inverter 11 and the second inverter 12 are controlled by the same control method. That is, the rotary electric machine control device 1 has a control mode in which the first inverter 11 and the second inverter 12 are controlled by the same control method, and a control mode in which the first inverter 11 and the second inverter 12 are controlled by different control methods.

In the above description, it has been described that the rotary electric machine control device 1 has pulse width modulation control, active short circuit control, and square wave control as control methods for the first inverter 11 and the second inverter 12. However, the rotary electric machine control device 1 is not limited to the form having these three control methods, and may have at least any two of these control methods. For example, the rotary electric machine control device 1 may have pulse width modulation control and active short circuit control as control methods for the first inverter 11 and the second inverter 12, or may have pulse width modulation control and a square wave. It may have wave control.

Although the details will be described later, in the present embodiment, the rotary electric machine control device 1 has four control modes (first control mode (mode1), second control mode (mode2), third control" as shown in Table 2 below. It has a mode (mode3) and a fourth control mode (mode4).

Of these, the first control mode (mode1) and the third control mode (mode3) are set to control modes in which the first inverter 11 is controlled by the first control method and the second inverter 12 is controlled by the second control method. Equivalent to. The first control method in the first control mode is pulse width modulation control (PWM), and the second control method is active short circuit control (ASC). The first control method in the third control mode is rectangular wave control (1-Pulse), and the second control method is pulse width modulation control (PWM). The combination of the first control method and the second control method in each control mode is an example, and other combinations may be used. Further, the types of control methods may include control methods other than active short circuit control (ASC), pulse width modulation control (PWM), and square wave control (1-Pulse).

In the first control mode, only one of the first inverter 11 and the second inverter 12 is controlled by the pulse width modulation control, and the other is controlled by the active short circuit control. In the embodiment shown in Table 2, only the first inverter 11 is controlled by the pulse width modulation control, and the second inverter 12 is controlled by the active short circuit control. When the second inverter 12 is controlled by the active short circuit control, it is equivalent to driving the rotary electric machine 80 by one inverter.

Pulse width modulation includes continuous pulse width modulation (CPWM) such as sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM: Space Vector PWM), and discontinuous pulse width modulation (discontinuous pulse width modulation). There are methods such as DPWM: Discontinuous PWM). In discontinuous pulse width modulation, for example, the signal level of the switching control signal of the inverter corresponding to one phase of the three-phase AC power is fixed in sequence, and the signal level of the switching control signal corresponding to the other two phases is changed. Let me. In continuous pulse width modulation, all phases are modulated without fixing the switching control signal corresponding to any phase in this way. These modulation methods have operating conditions such as rotational speed and torque required for the rotary electric machine 80, and the modulation factor required to satisfy the operating conditions (ratio of the effective value of the three-phase AC interphase voltage to the DC voltage). ) Is determined.

The first control mode and the second control mode are control modes when the operating conditions of the rotary electric machine 80 are low rotation speed and low torque as compared with the third control mode and the fourth control mode, and are pulse width modulation methods. Is continuous pulse width modulation. The third control mode is a control mode when the operating conditions of the rotary electric machine 80 are high rotation speed and high torque as compared with the second control mode, and the pulse width modulation method is continuous pulse width modulation and discontinuous pulse width. It is modulation. For example, in the third control mode, in the case of relatively low rotation speed / low torque, it is modulated by continuous pulse width modulation, and in the case of relatively high rotation speed / high torque, it is modulated by discontinuous pulse width modulation. Will be done.

In pulse width modulation, a pulse is generated based on the magnitude relationship between the amplitude of an AC waveform (for example, an AC voltage waveform) as an output command and the amplitude of a triangular carrier waveform (including a saw wave) (FIG. 8 and the like). reference.). In some cases, the PWM waveform is directly generated by digital calculation without comparison with the carrier, but even in that case, the amplitude of the AC waveform as a command value and the amplitude of the virtual carrier waveform have a correlation.

In pulse width modulation by digital calculation, the carrier is determined according to the control cycle of the rotary electric machine control device 1, such as the calculation cycle of a microcomputer or the operation cycle of an electronic circuit. That is, even when a plurality of phases of AC power are used to drive the AC rotary electric machine 80, the carrier is not constrained by the rotation speed or rotation angle (electrical angle) of the rotary electric machine 80 (period not synchronized). have. Therefore, neither the carrier nor each pulse generated based on the carrier is synchronized with the rotation of the rotary electric machine 80. Therefore, modulation methods such as sinusoidal pulse width modulation and space vector pulse width modulation may be referred to as "asynchronous modulation method". On the other hand, a modulation method in which a pulse is generated in synchronization with the rotation of the rotary electric machine 80 is called a "synchronous modulation method". For example, in the square wave control (square wave modulation), one pulse is output for each electric angle cycle of the rotary electric machine 80, so that the square wave modulation is a synchronous modulation method.

By the way, as an index showing the conversion rate from the DC voltage to the AC voltage, there is a modulation factor showing the ratio of the effective value of the line voltage of the multi-phase AC voltage to the DC voltage. Generally, the maximum modulation factor of sinusoidal pulse width modulation is about 0.61 (≈0.612), and the maximum modulation factor of space vector pulse width modulation control is about 0.71 (≈0.707). A modulation method having a modulation factor of more than about 0.71 is called "overmodulation pulse width modulation" as a modulation method having a modulation factor higher than usual. The maximum modulation factor of "overmodulation pulse width modulation" is about 0.78. This modulation factor of 0.78 is a physical (mathematical) limit value in power conversion from direct current to alternating current. In the overmodulation pulse width modulation, when the modulation factor reaches 0.78, it becomes a square wave modulation (1 pulse modulation) in which one pulse is output in one cycle of the electric angle. In square wave modulation, the modulation factor is fixed at the physical limit of about 0.78.

The overmodulation pulse width modulation having a modulation factor of less than 0.78 can be realized by using any principle of the synchronous modulation method and the asynchronous modulation method. A typical modulation method is discontinuous pulse width modulation. Discontinuous pulse width modulation can be realized by using either a synchronous modulation method or an asynchronous modulation method. For example, when the synchronous modulation method is used, in the square wave modulation, one pulse is output in one cycle of the electric angle, but in the discontinuous pulse width modulation, a plurality of pulses are output in one cycle of the electric angle. When a plurality of pulses are present in one cycle of the electric angle, the effective period of the pulses is reduced by that amount, so that the modulation factor is lowered. Therefore, not only the modulation factor fixed to about 0.78 but also any modulation factor less than 0.78 can be realized by the synchronous modulation method. For example, multi-pulse modulation (Multi-Pulses) such as 9-pulse modulation (9-Pulses) that outputs 9 pulses and 5-pulse modulation (5-Pulses) that outputs 5 pulses in one cycle of the electric angle may be used. It is possible.

By the way, when one inverter 10 is vector-controlled, eight space vectors can be defined according to the state of the three-phase arm 3A. Specifically, eight spatial vectors can be defined by combining the signal levels of the switching control signals of the upper switching element 3H (2 ^ 3 = 8). The signal level of the three-phase switching control signal of the lower switching element 3L is a signal level complementary to the switching control signal of the upper switching element 3H, respectively. Therefore, the space vector can be defined by the signal level of either the upper stage side or the lower stage side switching control signal.

When the signal level of each switching control signal is high level is "1", when the signal level is low level is "0", and the signal level of the U-phase, V-phase, and W-phase switching control signals is indicated by (UVW). There are eight space vectors (000), (001), (010), (011), (100), (101), (110), and (111). Of the eight space vectors, (000) and (111) are called zero vectors or null vectors because the interphase voltage becomes zero and no voltage is applied to the rotary electric machine 80, and they are called zero vectors or null vectors in the dq-axis vector coordinate system. Shows the same coordinates. On the other hand, the other six space vectors are called active vectors and show different coordinates in the dq-axis vector coordinate system.

As shown in FIG. 1, when two inverters 10 are vector-controlled, 64 spatial vectors can be defined by the signal level of either the upper stage side or the lower stage side switching control signal (2 ^). 6 = 64). Of these, 10 are null vectors. The signal levels of the U phase (U ₁ phase), V phase (V ₁ phase), W phase (W ₁ phase) of the first inverter 11 and the U phase (U ₂ phase), V phase (V ₂ ) of the second inverter 12. (Phase), W phase (W ₂ phase) signal level is indicated by (U ₁ V ₁ W ₁ -U ₂ V ₂ W ₂ ), (000-000), (001-001), (010-010). ), (011-011), (100-100), (101-101), (110-110), (111-111), (000-111), (111-000). Is a null vector where is zero. The remaining 54 are active vectors with valid magnitudes from the origin (null vector coordinates) to 18 different coordinates in the dq-axis vector coordinate system.

In FIG. 2, the coordinates of the null vector and the coordinates of the 18 active vectors are plotted. Z0 indicates the coordinates of the null vector in the dq-axis vector coordinate system (10 vectors have the same coordinates). Z1 to Z6 indicate the coordinates of the active vector realized by substantially one inverter 10 in the dq-axis vector coordinate system. Z7 to Z18 show the coordinates corresponding to the active vector realized by the two inverters 10 in the dq-axis vector coordinate system.

Z1 is (000-011), (100-000), (100-111), (111-011), Z2 is (000-001), (110-000), (110-111), (111-001). ), Z3 is (000-101), (010-000), (010-111), (111-101), Z4 is (000-100), (011-000), (011-111), (111). -100), Z5 is (000-110), (001-000), (001-111), (111-110), Z6 is (000-010), (101-000), (101-111), (111-010) is included. These 24 space vectors are a combination in which the space vector of one inverter 10 is a null vector and the space vector of the other inverter 10 is an active vector.

Z1: (101-001), (110-010), Z2: (010-011), (100-101), Z3: (011-001), (110-100), Z4: (001-101). ), (010-110), Z5: (011-010), (101-100), Z6: (001-011), (100-110), the 12 spatial vectors also have the coordinates of Z1 to Z6, respectively. show. However, one of the inverters 10 is not a null vector, and the two inverters 10 are both active vectors.

Z7 is (100-001), (110-011), Z8 is (010-001), (110-101), Z9 is (010-100), (011-101), Z10 is (001-100), (011-110), Z11 correspond to (001-010), (101-110), Z12 corresponds to 12 space vectors of (100-010), (101-011). Further, Z13 is (100-011), Z14 is (110-001), Z15 is (010-101), Z16 is (011-100), Z17 is (001-110), and Z18 is (101-010). Corresponds to 6 space vectors.

FIG. 3 shows the control region of the rotary electric machine 80 in relation to the rotation speed and the torque. The outermost solid line shows the control area realized by using two inverters 10, and the broken line shows the control area that can be realized by using one inverter 10. The first area R1 indicates the control area corresponding to the above-mentioned first control mode, the second area R2 indicates the control area corresponding to the second control mode, and the third area R3 corresponds to the third control mode. The fourth area R4 indicates the control area corresponding to the fourth control mode.

The first region R1 is a control region having the lowest rotation speed and low torque, and a control region in which the entire region of the first region R1 can be realized by using one inverter 10 (lower rotation speed than the broken line in FIG. 3).・ It is included in the low torque side). That is, in the first region R1, the rotary electric machine 80 can be driven by one inverter 10. In the present embodiment, as shown in Table 2, the second inverter 12 is short-circuited by active short circuit control, and the rotary electric machine 80 is driven and controlled by the first control mode in which the first inverter 11 is controlled by pulse width modulation.

The second region R2 is a control region having a higher rotation speed than the first region R1. As shown in FIG. 3, a part of the second region R2 is a control region that can be realized by using one inverter 10 on the side where the torque is high (the side having a lower rotation speed / torque than the broken line in FIG. 3). ) Includes regions with higher rotational speeds. That is, in the second region R2, the rotary electric machine 80 cannot be driven by one inverter 10 in the entire region, and the rotary electric machine control device 1 drives the rotary electric machine 80 by using the two inverters 10. Since the second region R2 is a control region having a relatively low rotation speed and low torque in the entire control region, a high modulation factor is not necessary. In the present embodiment, as shown in Table 2, the rotary electric machine 80 is driven and controlled by the second control mode in which both the first inverter 11 and the second inverter 12 are controlled by pulse width modulation.

The third region R3 is a control region having a higher rotation speed than the second region R2. As shown in FIG. 3, many regions of the third region R3, particularly the region on the high torque side, are control regions that can be realized by using one inverter 10 (lower rotation speed / lower than the broken line in FIG. 3). It is a region of higher rotation speed than the torque side). In the third region R3 as well as the second region R2, the rotary electric machine 80 cannot be driven by one inverter 10 in the entire region, and the rotary electric machine control device 1 uses the two inverters 10 to drive the rotary electric machine 80. Drive. Since the third region R3 is a control region having a relatively high rotation speed and high torque in the entire control region, a high modulation factor is required. In the present embodiment, as shown in Table 2, the rotary electric machine 80 is driven and controlled by the third control mode in which the first inverter 11 is controlled by a rectangular wave and the second inverter 12 is controlled by pulse width modulation.

For the pulse width modulation control in the third control mode, it is preferable to use space vector pulse width modulation and discontinuous pulse width modulation capable of outputting a modulation factor higher than that of space vector pulse width modulation. Since the first inverter 11 is controlled by synchronous modulation (rectangular wave modulation), when the second inverter 12 is also controlled by synchronous modulation, the phase of the AC voltage of the first inverter 11 and the AC voltage of the second inverter 12 are controlled. It is easy to make the phase 180 degrees different. As described above, discontinuous pulse width modulation can also be realized by synchronous modulation (multiple pulse modulation). As the pulse width modulation for controlling the second inverter 12 in the third control mode, it is preferable to use discontinuous pulse width modulation by synchronous modulation (plural pulse modulation).

The fourth region R4 is a control region having the highest rotation speed and high torque, and almost the entire region of the fourth region R4 except for a part of low torque cannot be realized by using one inverter 10 (in FIG. 3). It is included on the side of high rotation speed and high torque than the broken line of. As shown in Table 2, in the fourth region R4, the rotary electric machine 80 is driven by being controlled by the fourth control mode in which the two inverters 10 are both controlled by a rectangular wave.

As described with reference to Table 2, FIG. 2, FIG. 3, and the like, the rotary electric machine control device 1 independently controls the control method for controlling the first inverter 11 and the control method for controlling the second inverter 12. It can be changed. It is preferable that the rotary electric machine control device 1 changes each control method based on the rotation speed of the rotary electric machine 80. Alternatively, the rotary electric machine control device 1 has each control method based on the ratio of the effective value of the three-phase AC power to the DC power (for example, the modulation factor (which may be a command value or a converted value from the output voltage)). It is preferable to change. Further, the control method may be changed based on an index other than the rotation speed of the rotary electric machine 80 and the ratio of the effective value of the three-phase AC power to the DC power. For example, the control method may be changed based on the output torque of the rotary electric machine 80. Alternatively, the control method may be changed based on the three-phase AC power, the three-phase AC current, the three-phase AC voltage, and their effective values.

Further, when the rotary electric machine control device 1 can independently change the control method for controlling the first inverter 11 and the control method for controlling the second inverter 12, one of the outputs is equal to or higher than the other's output. It is preferable to set the control method of the first inverter 11 and the second inverter 12 so as to be. Specifically, in the following description, in addition to Table 2, Tables 3 and 4 and the like shown below will be referred to, and each inverter can be appropriately configured according to the operation of the two inverters. For example, the inverter that often operates at a relatively high output (for example, a relatively high modulation factor) is configured to be more reliable, and a relatively low output (for example, a relatively low modulation factor) is configured. ) Can be configured so that the inverter that often operates is not over-engineered.

Further, as described above, the third region R3 is a control region having a relatively high rotation speed and high torque in the entire control region. Therefore, when discontinuous pulse width modulation by synchronous modulation (multiple pulse modulation) is used as the pulse width modulation for controlling the second inverter 12 in the third control mode, the synchronous rotation speed becomes faster and the pulse frequency. Will also be higher. Even when asynchronous modulation (spatial vector pulse width modulation) is used as the pulse width modulation for controlling the second inverter 12, the carrier frequency tends to be high and the pulse frequency tends to be high because the rotation speed is high. ..

Since the control method of the first inverter 11 in the third control mode is rectangular wave control, the frequency of the pulse that controls the first inverter 11 is lower than that of the second inverter 12. In the second control mode, since the two inverters 10 are both pulse width modulation controlled, the pulse frequencies are the same. Further, in the first control mode, only the first inverter 11 is pulse width modulated, but since the rotation speed of the rotary electric machine 80 is low, the pulse frequency is lower than in the third control mode.

In the present embodiment, the first inverter 11 is an inverter 10 controlled by a pulse having a relatively low switching frequency when pulse width modulation control is executed. On the other hand, the second inverter 12 is an inverter 10 controlled by a pulse having a relatively high switching frequency when pulse width modulation control is executed. Therefore, the first inverter 11 is configured by using the first switching element 31 having a relatively large switching loss at the time of transition between the off state and the on state, and the second inverter 12 has a relative switching loss. It can be configured by using a second switching element 32 which is relatively small. For example, a Si-IGBT or Si-PLC can be used as the first switching element 31, and a SiC-PWM, a GaN-PWM, or a SiC-IGBT can be used as the second switching element 32.

Silicon carbide (SiC) is a compound semiconductor material composed of silicon (Si) and carbon (C). SiC has excellent physical properties that the dielectric breakdown electric field strength is about 10 times that of Si and the band gap is about 3 times that of Si. Further, SiC can control the p-type and n-type required for device fabrication in a wide range. Since the dielectric breakdown electric field strength of SiC is higher than that of Si, when a high withstand voltage power device is configured using SiC, the impurity concentration is higher and the film thickness is thinner than when the device is configured by Si. A drift layer can be formed. Since most of the resistance component of the high withstand voltage power device is the resistance of the drift layer, the on-resistance per unit area of the SiC device is much lower than that of the Si device. For example, if the withstand voltage is theoretically the same, the drift layer resistance of the SiC device can be reduced to about 1/300 per area as compared with the drift layer resistance of the Si device.

Further, the Si device is often configured as a minority carrier device (bipolar device) such as an IGBT in order to improve the increase in on-resistance accompanying a high withstand voltage. However, the IGBT has a large switching loss and generates a large amount of heat when driven at a high frequency. On the other hand, in the SiC device, high withstand voltage can be realized by a large number of carrier devices (Schottky barrier diode and MOSFET) having a high-speed device structure. That is, the SiC device can realize higher withstand voltage, lower on-resistance, and higher speed than the Si device. Further, since SiC has a wide bandgap, it is possible to realize a power device capable of operating at a higher temperature than Si. The same is true for gallium nitride (GaN). Therefore, as the second switching element 32, it is particularly preferable to use a SiC- MOSFET or a GaN-PWM.

By the way, in the above, with reference to Table 2, among the four control modes, the first control mode (mode1) and the third control mode (mode3) control the first inverter 11 by the first control method. , A mode corresponding to a control mode in which the second inverter 12 is controlled by the second control method is illustrated. For example, in the first control mode, the first control method is pulse width modulation control (PWM) and the second control method is active short circuit control (ASC). The first control method in the third control mode is rectangular wave control (1-Pulse), and the second control method is pulse width modulation control (PWM). However, the distinction between the first control method and the second control method is limited to the difference in control methods such as active short circuit control (ASC), pulse width modulation control (PWM), and square wave control (1-Pulse). It's not something. For example, even with pulse width modulation control (PWM), it can be said that the control method differs between continuous pulse width modulation (CPWM) and discontinuous pulse width modulation (DPWM), and even with discontinuous pulse width modulation. It can be said that the control method is different between asynchronous modulation and synchronous modulation. Table 3 below exemplifies a form different from that in Table 2.

As shown in Table 3, in the second control mode (mode2), when the first inverter 11 is controlled by discontinuous pulse width modulation (DPWM) and the second inverter 12 is controlled by continuous pulse width modulation (CPWM), the first The 1 inverter 11 is controlled by the first control method, and the second inverter 12 is controlled by the second control method. Further, as shown in Table 3, the third control mode (mode3) may be further subdivided to control the second inverter 12 by using a plurality of control methods.

As described above, the rotary electric machine control device 1 is based on the ratio of the effective value of the three-phase AC power to the DC power (for example, the modulation factor (which may be a command value or a converted value from the output voltage)). You can change the control method of. In the present embodiment, the terminal voltage "E1" of the first DC power supply 61 and the terminal voltage "E2" of the second DC power supply 62 are the same (both are voltage "E"). Assuming that the effective value on the AC side of the first inverter 11 is "Va_inv1" and the effective value on the AC side of the second inverter 12 is "Va_inv2", the modulation factor "Mi_inv1" of the first inverter 11 and the second inverter 12 The modulation factor "Mi_inv2" is as shown in the following equations (1) and (2). Further, the modulation factor "Mi_sys" of the entire system is as shown in the following equation (3).

Mi_inv1 = Va_inv1 / E1 = Va_inv1 / E ... (1)
Mi_inv2 = Va_inv2 / E2 = Va_inv2 / E ... (2)
Mi_sys = (Va_inv1 + Va_inv2) / (E1 + E2)
= (Va_inv1 + Va_inv2) / 2E ... (3)

Regarding the instantaneous value of the voltage, it is necessary to consider the vector as described later with reference to FIGS. 4 to 7, but if only the modulation factor is simply considered, the entire system can be understood from equations (1) to (3). The modulation factor "Mi_system" of is "(Mi_inv1 + Mi_inv2) / 2".

For example, the first control mode shown in Table 3 is selected when the modulation factor “Mi_sys” of the entire system is less than the first reference modulation factor M1 (for example, “0.25”). Since the second inverter 12 is controlled by an active short circuit, the modulation factor "Mi_inv2" is zero. Therefore, it is necessary to achieve the modulation factor "Mi_sys" of the entire system only by the first inverter 11. Therefore, the first inverter 11 has a modulation factor “Mi_inv1” of “0.6 = 0.25 × 2 + 0.” Including a margin α (for example, “0.1”) for preventing hunting between control modes. It is controlled by continuous pulse width modulation control (CPWM) in the range of less than 1 ”.

The second control mode is when the modulation factor “Mi_sys” of the entire system is equal to or higher than the first reference modulation factor M1 (for example, “0.25”) and less than the second reference modulation factor M2 (for example, “0.5”). Be selected. As shown in Table 2, when the first inverter 11 and the second inverter 12 are controlled by the same control method, the modulation rates “Mi_inv1” and “Mi_inv2” of both inverters are set to “0.25 to 0. The first inverter 11 and the second inverter 12 are controlled by continuous pulse width modulation control (CPWM) or discontinuous pulse width modulation control (DPWM) so as to be in the range of 5 ”. As shown in Table 3, when the first inverter 11 and the second inverter 12 are controlled by different pulse width control methods, the modulation factor “Mi_sys” of the entire system is “0.25 to 0.5”. The first inverter 11 is controlled by the discontinuous pulse width modulation control (DPWM), and the second inverter 12 is controlled by the continuous pulse width modulation control (CPWM) so that the range becomes “Mi_inv1> Mi_inv2”. Here, for example, the maximum value of the modulation factor “Mi_inv1” of the first inverter 11 in the second control mode is “0.56”, and the maximum value of the modulation factor “Mi_inv2” of the second inverter 12 is “0.44”. Suppose there is. As with the first control mode margin α, in order to prevent hunting between control modes, for example, a margin may be set on the upper limit side of the modulation factor range.

The third control mode is selected when the modulation factor "Mi_sys" of the entire system is the second reference modulation factor M2 (for example, "0.5") or more and the maximum modulation factor "0.78". Since the first inverter 11 is controlled by rectangular wave control (1-Pulse), its modulation factor "Mi_inv1" is fixed at "0.78". In order to satisfy the modulation factor "Mi_sys" of the entire system, the second inverter 12 is controlled within a range in which the modulation factor "Mi_inv2" is "0.22" or more and less than "0.78". On the side close to the lower limit modulation factor “0.22” within this range, the second inverter 12 is controlled by continuous pulse width modulation control (CPWM) as shown in Table 3. Further, on the side close to the upper limit modulation factor “0.78” within this range, the second inverter 12 is controlled by the multi-pulse modulation control (Multi-Pulses) as shown in Table 3. At an intermediate modulation factor within this range, the second inverter 12 is controlled by discontinuous pulse width modulation control (DPWM). As with the first control mode margin α, in order to prevent hunting between control modes, for example, a margin may be set on the lower limit side of the modulation factor range.

In the fourth control mode, the modulation factor "Mi_sys" of the entire system is fixed to the maximum modulation factor "0.78". Since both the first inverter 11 and the second inverter 12 are controlled by the rectangular wave control (1-Pulse), the modulation rates “Mi_inv1” and “Mi_inv2” of both inverters are fixed to “0.78”. In this way, the rotary electric machine control device 1 can change the control method based on the modulation factor (which may be a command value of the modulation factor or a converted value from the output voltage). Table 4 below shows the control modes in Table 3 with the above-mentioned classification according to the modulation factor. In addition, "a" and "b" in Table 4 are arbitrary values, for example, "a" is about "0.3-0.5" and "b" is "0.5-0.7". "It is preferable that it is about.

Although it is an index equivalent to the modulation factor, the rotary electric machine control device 1 is controlled based on the voltage command (voltage command "V1 ^* " of the first inverter 11 and voltage command "V2 ^* " of the second inverter 12). The method may be changed (see the voltage command Vu ^** etc. exemplified in FIG. 8 etc.). For example, in the first control mode, the voltage command “V1 ^* ” of the first inverter 11 is less than the first voltage command reference value (voltage command value corresponding to the first reference modulation factor M1), and the second inverter 12 has. Selected when the voltage command "V2 ^* " is zero. The fourth control mode is selected when the voltage command "V1 ^* " of the first inverter 11 and the voltage command "V2 ^* " of the second inverter 12 are the maximum values. Since it is easy to understand from the above description, detailed description and examples will be omitted, but similarly, the rotary electric machine control device 1 controls the second control mode and the third control mode based on the voltage command. The method can be changed.

By the way, as described above, when the control method for controlling the first inverter 11 and the control method for controlling the second inverter 12 can be changed independently, the rotary electric machine control device 1 can be used with both inverters (11, 12). ), It is preferable to change the control method of either of the inverters 10. If the control methods of the two inverters (11, 12) are changed at the same time, it becomes difficult to maintain the continuity of control, which may affect the rotation of the rotary electric machine 80. By changing the control method of one of the two inverters (11, 12) of the inverter 10 and changing the combination of the control methods of the two inverters (11, 12), the rotary electric machine 80 can be stably operated. Can be controlled.

For example, when the control method of the first inverter 11 and the control method of the second inverter 12 are the same control method, the control method of either of the inverters 10 is changed so that the control methods are different, and the first inverter When the control method of 11 and the control method of the second inverter 12 are different, the control method of either of the inverters 10 is changed so that different combinations of different control methods or the same control method are used. .. Table 5 below shows an example of changing the control method in this way. The mode illustrated in Table 5 is preferably switched according to, for example, the modulation factor. Further, although the specific modulation factor is not shown, also in the modes exemplified in Table 5, the mode 1 side has a low modulation factor and the mode 4 side has a high modulation factor as in the embodiment shown in Table 4.

In mode 1 shown in Table 5, the first inverter 11 is controlled by continuous pulse width modulation, the second inverter 12 is controlled by active short circuit control, and the two inverters (11, 12) are controlled by different control methods. Will be done. In mode2-1, both the first inverter 11 and the second inverter 12 are controlled by continuous pulse width modulation, and the two inverters (11, 12) are controlled by the same control method. When shifting from mode1 in which two inverters (11, 12) are controlled by different control methods to mode2-1 in which two inverters (11, 12) are controlled by the same control method, one of the inverters is used. The control method of the second inverter 12, which is 10, is changed from active short circuit control to continuous pulse width modulation control. When shifting from mode2-1 in which two inverters (11, 12) are controlled by the same control method to mode1 in which two inverters (11, 12) are controlled by different control methods, one of the inverters is used. The control method of the second inverter 12, which is 10, is changed from continuous pulse width modulation control to active short circuit control.

In mode2-2, the first inverter 11 is controlled by discontinuous pulse width modulation, the second inverter 12 is controlled by continuous pulse width modulation, and the two inverters (11, 12) are controlled by different control methods. To. When shifting from mode2-1 in which two inverters (11, 12) are controlled by the same control method to mode2-2 in which two inverters (11, 12) are controlled by different control methods, either The control method of the first inverter 11, which is one of the inverters 10, is changed from continuous pulse width modulation control to discontinuous pulse width modulation control. Similarly, when shifting from mode2-2 in which two inverters (11, 12) are controlled by different control methods to mode2-1 in which two inverters (11, 12) are controlled by the same control method. The control method of the first inverter 11, which is one of the inverters 10, is changed from the discontinuous pulse width modulation control to the continuous pulse width modulation control.

In mode3-1, the first inverter 11 is controlled by rectangular wave modulation, the second inverter 12 is controlled by continuous pulse width modulation, and the two inverters (11, 12) are controlled by different control methods. When migrating from mode2-2 in which two inverters (11,12) are controlled by different control methods to mode3-1 in which two inverters (11,12) are controlled by different control methods in different combinations. Is changed from the discontinuous pulse width modulation control to the square wave control in the control method of the first inverter 11 which is one of the inverters 10. Similarly, the transition from mode3-1 in which the two inverters (11,12) are controlled by different control methods to mode2-2 in which the two inverters (11,12) are controlled by different control methods in different combinations. At that time, the control method of the first inverter 11, which is one of the inverters 10, is changed from the square wave modulation control to the discontinuous pulse width modulation control.

In mode3-2, the first inverter 11 is controlled by square wave modulation, the second inverter 12 is controlled by discontinuous pulse width modulation, and the two inverters (11, 12) are controlled by different control methods. .. When migrating from mode3-1 in which two inverters (11,12) are controlled by different control methods to mode3-2 in which two inverters (11,12) are controlled by different control methods in different combinations. The control method of the second inverter 12, which is one of the inverters 10, is changed from continuous pulse width modulation to discontinuous pulse width modulation control. Similarly, the transition from mode3-2 in which the two inverters (11,12) are controlled by different control methods to mode3-1 in which the two inverters (11,12) are controlled by different control methods in different combinations. At that time, the control method of the second inverter 12, which is one of the inverters 10, is changed from the discontinuous pulse width modulation control to the continuous pulse width modulation control.

In mode 4, both the first inverter 11 and the second inverter 12 are controlled by rectangular wave modulation, and the two inverters (11, 12) are controlled by the same control method. When shifting from mode3-2 in which the two inverters (11,12) are controlled by different control methods to mode4 in which the two inverters (11,12) are controlled by the same control method, one of them is used. The control method of the second inverter 12 which is the inverter 10 is changed from the discontinuous pulse width modulation control to the square wave control. Similarly, when shifting from mode 4 in which the two inverters (11, 12) are controlled by the same control method to mode 3-2 in which the two inverters (11, 12) are controlled by different control methods, anytime The control method of the second inverter 12, which is one of the inverters 10, is changed from the square wave modulation control to the discontinuous pulse width modulation control.

Hereinafter, the first control mode to the fourth control mode will be described with reference to a voltage command and, in part, an example of waveforms of the output voltage and the interphase voltage of the inverter 10, focusing on the modes illustrated in Table 2.

FIG. 4 illustrates a vector diagram at one operating point in the dq-axis vector coordinate system of the rotary electric machine 80, which is driven and controlled in the first control mode. In the figure, “V1” indicates a first voltage vector indicating the voltage generated by the first inverter 11, and “V2” indicates a second voltage vector indicating the voltage generated by the second inverter 12. The voltage appearing in the stator coil 8 which is an open winding through the two inverters 10 corresponds to the difference “V1-V2” between the first voltage vector V1 and the second voltage vector V2. “Va” in the figure indicates a combined voltage vector appearing in the stator coil 8. In the first control mode, the second inverter 12 is actively short-circuit controlled, and the second voltage vector V2 is a null vector. Therefore, the combined voltage vector Va coincides with the first voltage vector V1. Further, "Ia" indicates the current flowing through the stator coil 8 of the rotary electric machine 80. The same applies to FIGS. 5 to 7, which show vector diagrams in the second control mode to the fourth control mode.

The waveform diagram of FIG. 8 shows the first U-phase voltage command Vu1 ^** , which is the U-phase voltage command of the first inverter 11 in the first control mode, and the second U-phase voltage command Vu2, which is the U-phase voltage command of the second inverter 12. ^** and an example of the carrier CA at the time of pulse width modulation are shown. In the present embodiment, the carrier CA is a triangular wave whose wave height changes between "1", that is, "0" and "1". The voltage command changes in a range where the minimum value is larger than "0" and the maximum value is smaller than "1". In sinusoidal pulse width modulation, the voltage command is sinusoidal, but the maximum modulation factor remains at about 0.61. In the present embodiment, the sinusoidal voltage command is corrected in order to perform space vector pulse width modulation having a maximum modulation factor of about 0.71.

As described above, in the first control mode, the second inverter 12 is short-circuited by the active short circuit control, and only the first inverter 11 functions as the inverter 10. For example, the maximum amplitude of the U-phase voltage is "(2/3) E" with the voltage of the DC power supply 6 as "E" (see also the vector diagram of FIG. 2), and the maximum amplitude of the interphase voltage is also the DC power supply 6 The voltage of is "E" and is "E".

FIG. 5 illustrates a vector diagram at one operating point in the dq-axis vector coordinate system of the rotary electric machine 80 that is driven and controlled in the second control mode. The waveform diagrams of FIGS. 9 and 10 show the first U-phase voltage command Vu1 ^** , which is the U-phase voltage command of the first inverter 11 in the second control mode, and the second U-phase, which is the U-phase voltage command of the second inverter 12. The voltage command Vu2 ^** and an example of the carrier CA are shown. The first U-phase voltage command Vu1 ^** in FIG. 9 illustrates a case where the first inverter 11 is modulated by continuous pulse width modulation (CPWM). Further, the first U-phase voltage command Vu1 ^** in FIG. 10 illustrates a case where the first inverter 11 is modulated by discontinuous pulse width modulation (DPWM) (see Tables 3 and 4). form.). The first U phase voltage command Vu1 ^** and the second U phase voltage command Vu2 ^** have phases that are approximately 180 degrees different. When the modulation factors are the same, when the vector of the current "Ia" and the vector of the voltage "V2" by the second inverter 12 ride on the same straight line (when the directions are different by 180 degrees), the power factor of the second inverter 12 becomes. It becomes "1". As a result, the second inverter 12 can be operated with high efficiency to optimize the system loss.

Unlike the first control mode, the second inverter 12 is not in a short-circuited state, and the first inverter 11 and the second inverter 12 are functioning effectively. Therefore, the maximum amplitude of the U-phase voltage is 2 in the first control mode. It is doubled to "(4/3) E" (see also the vector diagram in FIG. 2), and the maximum amplitude of the interphase voltage is "2E". The first DC power supply 61 and the second DC power supply 62 are independent of each other, and the first DC voltage E1 of the first DC power supply 61 and the second DC voltage E2 of the second DC power supply 62 have different values. There may be. For example, to be precise, the maximum amplitude of the U-phase voltage is "((2/3) E1) + (2/3) E2", but in the present specification, "E1 =" including the following explanation. This will be described as "E2 = E".

FIG. 6 illustrates a vector diagram at one operating point in the dq-axis vector coordinate system of the rotary electric machine 80, which is driven and controlled in the third control mode. The waveform diagrams of FIGS. 11 and 12 show the first U-phase voltage command Vu1 ^** , which is the U-phase voltage command of the first inverter 11 in the third control mode, and the second U-phase, which is the U-phase voltage command of the second inverter 12. The voltage command Vu2 ^** and an example of the carrier CA are shown. In the third control mode, since the first inverter 11 is controlled by a rectangular wave, the first U phase voltage command Vu1 ^** also has a rectangular wave shape. FIG. 11 illustrates a mode in which the second U-phase voltage command Vu2 ^** is similar to the second control mode (voltage command for continuous pulse width modulation (CPWM) such as space vector pulse width modulation (SVPWM)). In FIG. 12, as described above with reference to Tables 3 and 4, the second U-phase voltage command Vu2 ^** may be a voltage command for discontinuous pulse width modulation (DPWM). Further, the second inverter 12 may be subjected to the same synchronous modulation as the rectangular wave modulation such as a plurality of pulse modulation (discontinuous pulse width modulation). When both the first inverter 11 and the second inverter 12 are synchronously modulated, the carrier CA is unnecessary.

Since the first inverter 11 and the second inverter 12 are functioning effectively in the third control mode as in the second control mode, the maximum amplitude of the U-phase voltage is "(4/3) E", and the interphase voltage. The maximum amplitude of is "2E".

FIG. 7 illustrates a vector diagram at one operating point in the dq-axis vector coordinate system of the rotary electric machine 80, which is driven and controlled in the fourth control mode. Here, the first inverter 11 and the second inverter 12 are controlled by a square wave having a phase difference of 180 degrees, and the first voltage vector V1 by the first inverter 11 and the second voltage vector V2 by the second inverter 12 The direction of the vector is different by 180 degrees. Therefore, as shown in FIG. 7, the combined voltage vector Va is a vector obtained by adding the magnitude of the second voltage vector V2 to the direction of the first voltage vector V1.

The waveform diagram of FIG. 13 shows the first U-phase voltage command Vu1 ^** , which is the U-phase voltage command of the first inverter 11 in the fourth control mode, and the second U-phase voltage command Vu2, which is the U-phase voltage command of the second inverter 12. ^** and an example of carrier CA are shown. In the fourth control mode, since the second inverter 12 is also controlled by a rectangular wave in addition to the first inverter 11, both the first U phase voltage command Vu1 ^** and the second U phase voltage command Vu2 ^** have a rectangular wave shape. When both the first inverter 11 and the second inverter 12 are square wave modulated (synchronous modulation), the carrier CA is not required, but the first control mode, the second control mode, and the like regarding the modulation factor and the like. The carrier CA is also shown for easy comparison with the third control mode.

The waveform diagram of FIG. 14 shows an example of the U-phase voltage of the fourth control mode, and the waveform diagram of FIG. 15 shows an example of the U-V phase voltage of the fourth control mode. Since the first inverter 11 and the second inverter 12 are functioning effectively even in the fourth control mode, the maximum amplitude of the U-phase voltage is "(4/3) E" as shown in FIG. Further, as shown in FIG. 15, the maximum amplitude of the interphase voltage is “2E”.

In the above, the first inverter 11 is connected to the first DC power supply 61 to convert power between DC and a plurality of phases of AC, and the second inverter 12 is independent of the first DC power supply 61. A mode of converting electric power between a direct current and a multi-phase alternating current connected to the second direct current power supply 62 has been described as an example. However, the first inverter 11 and the second inverter 12 connected to the same DC power supply 6 may be controlled independently.

[Outline of Embodiment]
Hereinafter, the outline of the rotary electric machine control device (1) described above will be briefly described.

The rotary electric machine control device (1) for driving and controlling a rotary electric machine (80) having a plurality of phases of open windings (8) independent of each other via a first inverter (11) and a second inverter (12) is 1. As one aspect,
The first inverter (11) is connected to one end side of the multi-phase open winding (8) to convert power between direct current and multi-phase alternating current.
The second inverter (12) is connected to the other end of the multi-phase open winding (8) to convert power between direct current and multi-phase alternating current.
In the first inverter (11) and the second inverter (12), the arm (3A) for one AC phase is composed of a series circuit of an upper switching element (3H) and a lower switching element (3L), respectively. ,
As the control method of the first inverter (11) and the second inverter (12), pulse width modulation control in which a plurality of pulses having different patterns are output in one cycle of the electric angle and the arm (3A) of all the plurality of phases are used. ), The active short circuit control that turns on the upper switching element (3H) or turns on the lower switching element (3L) of all the arms (3A) of the plurality of phases, and one cycle of the electric angle. It has at least two control methods among the square wave control in which one pulse is output in the above.
The first inverter (11) and the second inverter (12) can be controlled by the independent control methods.
One of the plurality of control methods is defined as the first control method, and one control method different from the first control method is used as the second control method.
It has a control mode in which the first inverter is controlled by the first control method and the second inverter is controlled by the second control method.

As a control method for controlling the inverter (10), various methods according to operating conditions such as the rotation speed and torque of the rotary electric machine (80) are known. When two inverters (10) are provided as in this configuration, it is possible to generate an AC voltage having an amplitude larger than the voltage on the DC side. However, the rotary electric machine control device (1) does not always need to control the two inverters (10) so that the amplitude of the alternating current becomes the largest, and the two inverters (10) so that the required amplitude can be obtained. ) May be controlled. By controlling the first inverter (11) and the second inverter (12) by independent control methods, the two inverters (10) can be flexibly controlled according to the operating conditions of the rotary electric machine (80). Can be done. Further, by having a control mode in which the first inverter (11) and the second inverter (12) are controlled by different control methods, the flexibility of control is increased and the efficiency is high according to the operating conditions of the rotary electric machine (80). The rotary electric machine (80) can be driven and controlled by. That is, according to this configuration, it is possible to appropriately control the two inverters (10) provided at both ends of the open winding (8).

As one embodiment, it is preferable to control only one of the first inverter (11) and the second inverter (12) by the pulse width modulation control and the other by the active short circuit control. ..

According to this configuration, by controlling one of the inverters (10) in an active short circuit, it is possible to realize an operation mode in which the rotary electric machine (80) is driven by one inverter (10).

Further, as one embodiment, the first inverter (11) and the first inverter (11) and the first inverter (12) so that the output of any one of the first inverter (11) and the second inverter (12) is equal to or higher than the output of the other. 2 It is preferable that the control method of the inverter (12) is set.

According to this configuration, the inverter (10) that often operates at a relatively high output is configured to have higher reliability, and the inverter (10) that often operates at a relatively low output is configured ( 10) can be appropriately configured according to the operation of the two inverters (11, 12), such as being configured so as not to have excessive performance.

Further, the control method for controlling the first inverter (11) and the control method for controlling the second inverter (12) can be changed independently, and the rotary electric machine control device (1) can be used as described above. It is preferable to change each of the control methods based on the rotation speed of the rotary electric machine (80).

The operating conditions of the rotary electric machine (80) are often defined by the relationship between the rotation speed and the torque. When the rotary electric machine control device (1) changes the control method for controlling the first inverter (11) and the second inverter (12) based on the rotation speed which is one parameter, the operating condition of the rotary electric machine (80) is changed. The rotary electric machine (80) can be driven and controlled with high efficiency.

Alternatively, when the control method for controlling the first inverter (11) and the control method for controlling the second inverter (12) can be changed independently, the rotary electric power control device (1) may be used. It is preferable to change each of the control methods based on the ratio of the effective value of the three-phase AC power to the DC power.

For example, when a rotary electric machine (80) is required to have a high output (fast rotation speed and high torque), in a voltage type inverter, the DC voltage is increased and the ratio of the DC voltage converted to an AC voltage is increased. By doing so, the requirement is realized. When the DC voltage is constant, the requirement can be realized by increasing the ratio of the DC voltage converted to the AC voltage. This ratio can be shown as the ratio of the effective value of the three-phase AC power to the DC power (in the case of a voltage type inverter, it is equivalent to the ratio of the effective value of the three-phase AC voltage to the DC voltage). There are various control methods for controlling the inverter (10), from those having a low ratio to those having a high ratio. By changing the control method based on the ratio of the effective value of the three-phase AC power to the DC power determined according to the demand for the rotary electric machine (80), it rotates with high efficiency according to the operating conditions of the rotary electric machine (80). The electric machine (80) can be driven and controlled.

When the control method for controlling the first inverter (11) and the control method for controlling the second inverter (12) can be changed independently, one embodiment is a rotary electric machine control device (1). ) Is the control method of the first inverter (11) and the control method of the first inverter (11) when the control method of the second inverter (12) is the same. 2 One of the control methods is changed so that the control method of the inverter (12) is different from that of the control method of the first inverter (11) and the second inverter (12). In the case of the control method having different control methods, the control method of the first inverter (11) and the control method of the second inverter (12) are different combinations of the different control methods or the same control. It is preferable to change one of the control methods so that the method becomes a method.

If the control methods of the two inverters (11, 12) are changed at the same time, it becomes difficult to maintain the continuity of control, which may affect the rotation of the rotary electric machine (80). By changing the control method of one of the two inverters (11, 12) (10) and changing the combination of the control methods of the two inverters (11, 12), the rotary electric machine (80) can be stably operated. ) Can be controlled.

Here, the pulse width modulation control includes continuous pulse width modulation and discontinuous pulse width modulation as a plurality of different control methods, and the continuous pulse width modulation is a sinusoidal wave as a plurality of different control methods. The discontinuous pulse width modulation includes pulse width modulation and spatial vector pulse width modulation, and the discontinuous pulse width modulation includes asynchronous modulation in which a pulse is output without being synchronized with the rotation of the rotary electric machine and the rotation as a plurality of different control methods. It includes synchronous modulation in which pulses synchronized with the rotation of the electric machine are output, and it is preferable that the synchronous modulation includes multiple pulse modulation in which a plurality of pulses are output per cycle of the electric angle of the rotary electric machine.

There are various different methods for pulse width modulation control. By controlling the first inverter (11) and the second inverter (12) by pulse width modulation control of different methods, the two inverters (10) can be flexibly controlled according to the operating conditions of the rotary electric machine (80). Can be controlled.

Further, of the first inverter (11) and the second inverter (12), one of the inverters (10) controlled by a pulse having a relatively low switching frequency when the pulse width modulation control is executed is , The first switching element (31), which has a relatively large switching loss at the time of transition between the off state and the on state, is used, and the switching is relatively high when the pulse width modulation control is executed. It is preferable that the other inverter (10) controlled by a pulse of frequency is configured by using the second switching element (32) having a relatively small switching loss.

One of the plurality of control methods is controlled by the first control method, one control method different from the first control method is used as the second control method, and the first inverter (11) is controlled by the first control method. When the second inverter (12) is controlled by the second control method, for example, the first inverter (11) may be controlled by the square wave control, and the second inverter (12) may be controlled by the pulse width modulation control. .. Comparing the pulse cycle in the square wave control and the pulse cycle in the pulse width modulation control, the electric voltage is compared with the pulse in the square wave control in which one cycle of the pulse is output in synchronization with one cycle of the electric angle. The pulse width modulation control pulse, in which a large number of pulses are output in one cycle of the angle, has a shorter pulse cycle and a higher switching frequency. In this case, the switching frequency of the second inverter (12) is higher than the switching frequency of the first inverter (11). In the opposite case, for example, when the first inverter (11) is controlled by pulse width modulation control and the second inverter (12) is controlled by square wave control, the switching of the second inverter (12) is performed in the same manner. The switching frequency of the first inverter (11) is higher than the frequency.

When a high output (high rotation speed and high torque) is required for the rotary electric machine (80), the switching frequency in the pulse width modulation control also tends to be high. Of course, for the same switching loss, the higher the switching frequency, the greater the total amount of loss. Since the first inverter (11) and the second inverter (12) are controlled independently, their respective circuits can be configured independently. Therefore, for the inverter (10) on the side where the switching frequency may be high, it is preferable to have a circuit configuration in which the switching loss is relatively small. That is, when the pulse width modulation control is executed, the inverter (10) controlled by the pulse having a relatively high switching frequency has a relatively small switching loss as compared with the first switching element (31). The loss can be reduced by being configured by using the two switching elements (32).

Here, it is preferable that the first switching element (31) is a Si-IGBT or Si-PWM, and the second switching element (32) is a SiC-PWM, a GaN-PWM, or a SiC-IGBT. be.

For example, since silicon carbide (SiC) has a higher dielectric breakdown electric field strength than silicon (Si), it is possible to form a drift layer with a high impurity concentration and a thin film thickness when forming a high withstand voltage power device. .. Since most of the resistance component of the high withstand voltage power device is the resistance of the drift layer, the on-resistance per unit area of the SiC device is lower than that of the Si device. That is, the SiC device can have a smaller switching loss than the Si device. The same applies to devices using gallium nitride (GaN). Therefore, when the first switching element (31) is a Si device, by using the SiC device or the GaN device as the second switching element (32), the switching loss is relatively smaller than that of the first switching element (31). The inverter (10) can be configured by using a small second switching element (32).

1: Rotating electric machine control device 3: Switching element 3A: Arm 3H: Upper stage side switching element 3L: Lower stage side switching element 8: Stator coil (open winding)
10: Inverter 11: First inverter 12: Second inverter 31: First switching element 32: Second switching element 80: Rotating electric machine

Claims (7)

A rotary electric machine control device that drives and controls a rotary electric machine having a plurality of phases of open windings that are independent of each other via a first inverter and a second inverter.
The first inverter is connected to one end side of the multi-phase open winding to convert power between direct current and multi-phase alternating current.
The second inverter is connected to the other end of the multi-phase open winding to convert power between direct current and multi-phase alternating current.
In the first inverter and the second inverter, the arm for one AC phase is composed of a series circuit of an upper switching element and a lower switching element, respectively.
As the control method of the first inverter and the second inverter, pulse width modulation control in which a plurality of pulses having different patterns are output in one cycle of the electric angle and the upper switching element of the arm of all the plurality of phases are turned on. It has an active short circuit control in which the lower switching element of the arm in a state or a plurality of phases is turned on, and a square wave control in which one pulse is output in one cycle of the electric angle.
The first inverter and the second inverter can be controlled by the independent control methods.
As a control mode for controlling the first inverter and the second inverter,
The first control mode in which the control method of the first inverter is the pulse width modulation control and the control method of the second inverter is the active short circuit control.
A second control mode in which the control method of the first inverter is the pulse width modulation control and the control method of the second inverter is the pulse width modulation control.
A third control mode in which the control method of the first inverter is the rectangular wave control and the control method of the second inverter is the pulse width modulation control.
A fourth control mode in which the control method of the first inverter is the square wave control and the control method of the second inverter is the square wave control.
Equipped with
The control method for controlling the first inverter and the control method for controlling the second inverter can be changed independently.
In the running control mode, when the control method of the first inverter and the control method of the second inverter are the same, the control method of the first inverter and the control method of the second inverter are described. By changing only one of the control method of the first inverter and the control method of the second inverter, the control mode is changed to a different control method so that the control method is different.
In the running control mode, when the control method of the first inverter and the control method of the second inverter are different from each other, the control method of the first inverter and the control method of the second inverter are described. By changing only one of the control method of the first inverter and the control method of the second inverter so that the control method becomes the control method having a different combination or the same control method. A rotary electric machine control device that changes to a different control mode . The first aspect of claim 1, wherein the control method of the first inverter and the second inverter is set so that the output of either one of the first inverter and the second inverter is equal to or higher than the output of the other inverter. Inverter controller. The rotary electric machine control device according to claim 1 or 2, wherein the control method is changed based on the rotational speed of the rotary electric machine. The rotary electric control device according to claim 1 or 2, wherein the control method is changed based on the ratio of the effective value of the three-phase AC power to the DC power. The pulse width modulation control includes continuous pulse width modulation control and discontinuous pulse width modulation control as a plurality of different control methods.
The second control mode further
The first second control mode in which the control method of the first inverter is the continuous pulse width modulation control and the control method of the second inverter is the continuous pulse width modulation control.
A second second control mode in which the control method of the first inverter is the discontinuous pulse width modulation control and the control method of the second inverter is the continuous pulse width modulation control.
Equipped with
The third control mode further
The first third control mode in which the control method of the first inverter is the rectangular wave control and the control method of the second inverter is the continuous pulse width modulation control.
A second third control mode in which the control method of the first inverter is the rectangular wave control and the control method of the second inverter is the discontinuous pulse width modulation control.
The rotary electric machine control device according to claim 3 or 4. Of the first inverter and the second inverter, one of the inverters controlled by a pulse having a relatively low switching frequency when the pulse width modulation control is executed is between an off state and an on state. The other inverter, which is configured by using the first switching element having a relatively large switching loss at the time of transition and is controlled by a pulse having a relatively high switching frequency when the pulse width modulation control is executed, is the switching. The rotary electric machine control device according to any one of claims 1 to 5, which is configured by using a second switching element having a relatively small loss. The rotary electric control device according to claim 6, wherein the first switching element is a Si-IGBT or a Si-PWM, and the second switching element is a SiC-PWM, a GaN-PWM, or a SiC-IGBT.

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